Magnetic baffle separator



April 11, 1961 A. ORBELIANI MAGNETIC BAFFLE SEPARATOR Filed Dec. 30, 1958 2 Sheets-Sheet 1 Andre Orbe/iani 1N VEN TOR.

April 11, 1961 A. ORBELIANI 2,979,202

MAGNETIC BAFFLE SEPARATOR Filed Dec. 50, 1958 2 Sheets-Sheet 2 Fig. 4

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9 BY m United States Patent MAGNETIC BAFFLE SEPARATOR Andre Orbeliani, Salrno, British Columbia, Canada Birkett Creek Mine Operators, Merritt, British Columbia, Canada) Filed Dec. 30, 1958, Ser. No. 783,747

6 Claims. (Cl..209.-223)- This invention relates to magnetic separators and more particularly to a magnetic baffle for the separation of magnetic and non-magnetic particles.

Although magnetic and electromagnetic ore separators have been previously disclosed, this invention provides improvements in and over prior magnetic separators by deflecting the particles susceptible to magnetization from a heterogeneous stream containing magnetic and nonmagnetic particles by a new technique. Heretofore strong electromagnetic fields have been produced adjacent to quantities of magnetic, usually ore particles to attract the particles while leaving the non-magnetic particles. The present invention increases both speed and efliciency by having a stream of particles, either wet or dry, move along a predetermined path, and subjecting the stream to an intense magnetic field arranged across the general flow direction of the stream but at an angle to it. Preferably, the field strength is considerably decreased at one edge of the stream so that the magnetic particles leave the field as they are discharged from the stream. Meanwhile the main body of the stream continues to move with respect to the magnetic field which is produced and arranged in the manner described.

It is not material whether the stream is fixed and the magnetic field movable with reference to the stream, although a more practical application of the invention has the stream flowing with the magnetic field in a fixed position so that the stream of particles flows through the magnetic field. Further, the angularity of the stream magnetic bafl le may be varied for optimum separation. In one embodiment of the invention the magnetic field extends transversely across the stream making an angle of approximately 20 with the general direction of movement of the stream.

An object of the invention is to provide a magnetic baffle consisting essentially of an intense magnetic field or means to produce an intense magnetic field transversely across a flowing stream of magnetic and nonmagnetic particles so that as the stream is propelled in its path of travel, the magnetic particles only are de flected by the action of the magnetic field, toward one edge of the flowing stream. There are, then, two forces reacting on the magnetic particles as they pass through the magnetic bafile. One force is that which is mechanically produced, for example by hydraulic or pneumatic propulsion of the heterogeneous stream, and the other is the force produced by the action of the magnetic field on the particles while they are propelled hydraulically, pneumatically or by other means in a constrained path of travel. 1

In order to achieve better results the means producing the magnetic field consist of thin ribs located in direct by a pan which supports the heterogeneous mass of flowing particles. These ribs are arranged at an angle to the ,general flow direction, as aforesaid, and there is acornparatively high flux density across the ribs since they are of small cross-sectional area. The ribs, arranged in pairs, are spaced apart an appreciable distance along one edge of the stream and are closer together near the opposite edge of the stream and across the middle of the stream. The wide spacing at one edge of the stream is to reduce the field strength along the stream edge to facilitate the separation of the magnetic particles from the stream; The particles in the low field strength region of the stream are more easily pushed by the forces propelling the particles of the stream, from the stream and, into a discharge port from which they may be collected. The unwanted non-magnetic particles are easily extracted from the stream since they will be concentrated (due to the separation of the magnetic particles) along theledge of the stream opposite to that, having the higher concentration magnetic particles displaced thereto by the magnetic baffle.

In practice of the invention the heterogeneous stream may be caused to move in a circular path of travel by having the pan function as a centrifuge, or may be moved in a circular path by hydraulic flushing, pneumatic pro pulsion or other mechanical means or devices. The various shapes of the pan, pole pieces and the arrange.- ment of ports may be varied considerably to achieve optimum separation for given types of ores or other magnetic particles. Other variables are the vehicle in which the particles are suspended when liquid or pneumatic propulsion is used, the field strength and a number of other engineering design factors.

Another object of the invention is to provide a new method of separating magnetic particles and non-magnetic particles from a heterogeneous stream of particles wherein the particles are moved in a particular path and an intense magnetic field is produced across the stream and at an angleto the general path of travel 'of the par.- ticles'in the stream so that the magnetic particles only are deflected to one edge of the stream as they are moved in their path of travel with the moving stream. The magnetic particles, being separated in this way to one part of the stream are easily extracted inasmuch as they are concentrated in one part of the stream and ultimately moved out of the stream and into collection portsor other means to collect the magnetic particles. During the time that the stream continues to move in its path of travel the non-magnetic particles may at least, in part, be withdrawn from the stream comparatively-easily since a very high percentage of the magneticv particles are moved toward one edge of the stream, assuming an approximately circular path of travel of the stream, leaving a part of the stream with a high concentration of non-magnetic particles. In fact, by having ports at the outer edges of the pan or other container for the stream, the non-magnetic particles may be centrifugally discharged through ports in the outer wall or edge of the pan.

Other objects and features of importance will become apparent in following the description of the illustrated form of the invention and the description of the process of separating magnetic and non-magnetic particles.

Figure l is a perspective view diagrammatically representing a typical separator constructed inaccordance with the invention.

Figure 2 is a sectional of Figure 1.

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure 2, parts of the flux return structure being omitted.

Figure 4 is a cross-sectional view taken on the line 4-4 of Figure 2, parts of. the flux return structure of the electromagnetic being omitted.

view taken on the line 2--2 Figure 5 is an enlarged fragmentary sectional view taken on the line 5-5 of Figure 4 and showing the construction of a typical pole piece.

Figure 6 is a diagrammatic top view to show a part of the procedure in the practice of the method.

Figure 7 is an elevational view of the structure in Figure 5. t

Figure 8 is an end view of the structure in Figure 5.

In the accompanying drawings there is a magnetic separator 10 into which a heterogeneous stream of magnetic and non-magnetic particles is introduced, for instance by a pump. The stream may be wet or dry and introduced into the separator 10 by any conventional means, for example a pump or compressor (not shown). When wet separation is desired, the stream is hydraulically propelled, consisting of a pulp made of a mixture of finally ground mineral ores or ore, water and unwanted non-magnetic impurities. The stream of magnetic and non-magnetic substance is introduced into a circular chamber 12 constructed of an inner cylindrical wa'l 14, an outer cylindrical wall 16 and a bottom wall 18 of a pan 20. The pan is made of non-magnetic material, for instance plastic, and has one or more inlet ports 22 and 24, for example, and one or more outlet ports, for example ports 26 and 28. Each of the ports is tangential or approximately tangential to the stream in chamber 12 and is in the outer cylindrical wall 16. The supply of material is applied under pressure into chamber 12 through conduits 30 and 32 which are connected to inlet ports 22 and 24. As will be seen subsequently, the non-magnetic particles are centrifugally driven toward the outer wall 18 and are withdrawn through conduits 36 and 38 that are in registry with outlet ports 26 and 28.

There are means for producing an intense magnetic field across the stream in chamber 12. These means consist of an electromagnet 40 having an electromagnetic coil 42 provided with a core 44 which forms part of a flux return structure. The remainder of the flux return structure consists of a casing 46 that has side wall 48, top wall 50 and a bottom wall 52. Wall 48 is cylindrical with the lower edge 54 spaced from the upper surface 56 of wall 52. Two pole pieces 58 and 60 are located in the in order to increase the distance between pole pieces along the inner edge of the stream of particles. This is to facilitate withdrawal of the magnetic particles from the magnetic field, as the magnetic particles are directed toward the inner edge of the stream. The magnetic particles approach, enter and pass through the inner edge of the stream by flowing through ports 76 and 78 in wall 14 of the pan 20 and drop through ports 62 so that they may be easily recovered.

In the method of extracting magnetic particles from a stream having a heterogeneous collection of magnetic and non-magnetic particles, preferably suspended in an aquespace between edge 54 and surface 56, the pole pieces or attached to core 44. Coil 42 may be energized by AC or DC current.

The two pole pieces 58 and are similarly constructed, pole piece 60 shown in detail in Figures 4 and 5. It is made of an annular ring 68 having a plurality of smoothly curved ribs 69 which are tapered to a comparatively narrow upper edge (Figure 5). -The ribs are uniformly spaced from each other and are so located with reference to the stream that they transversely cross the stream but not at right angles to the stream. The ribs 69 cross the stream at an angle of about 20 more or less as measured in the general direction of travel of the stream and the general direction of the ribs 69. The upper pole piece 68 is identical, and has ribs 70 parallel and spaced from the ribs 69. A flux gap is established between the adjacent edges of the ribs in each pair on the two pole pieces 58 and 60. Pan 20 has its bottom wall 18 resting on or otherwise supported above pole piece 60, and the upper wall 21 of the pan 20 is immediately adjacent to the ribs 70 of pole piece 58. The pole pieces and means for energizing the pole pieces to produce a high intensity magnetic field across the flux gap and arranged across the stream of particles, constitutes a magnetic bafile for deflecting the magnetic particles as they are propelled in the stream as confined by the top, bottom and side walls of chamber 12.

As shown in Figure 5 the ribs 69 have their inner parts reduced in height, and the same holds true for ribs 70 ous vehicle, entails several steps which may be practiced by the apparatus illustrated in the drawings or by numerous other apparatus and equipment. As shown in Figure 6 the process of separating magnetic and non-magnetic particles consists of producing a flowing stream having a heterogeneous mass of magnetic and non-magnetic particles. The stream is indicated by the arrows (Figure 7) and is made to flow in a constrained path, for instance between a pair of plates 102 and 104. An intense magnetic field is produced across the stream 100 and at an angle which may be varied within wide lim'ts but which has been found to be effective in the range of 10 to 60. The diagrammatic illustration shows the angle made with the stream to be 20. The field strength at one edge of the stream, for example the outer edge and along the major part of the width of the stream is uniform, but the field strength along the opposite edge of the stream is considerably weakened. This may be achieved in a number of ways depending on the electromagnetic circuit or permanent magnet circuit or arrangement that is adopted. One simple way of obtaining this result is to increase a distance 104 between pole pIeces (Figure 7). as compared to the distance between pole pieces along the major part of the width of the stream and of the first mentioned edge of the stream. The nonmagnetic particles, being pneumatically or hydraulically propelled and uninfluenced by the magnet'c field, continue to flow along a determinable path. When a circular stream is established, for instance by a circular pan, the non-magnetic particles will flow in a circular path of travel and there will be a component of centrifugal force urging the non-magnetic particles toward the outer edge of the circular stream. The nonmagnetic particles, then, may be easily withdrawn from the stream by ports as ports 26 and 28 from the outer edge of the stream. At the same time, though, the magnetic particles are deflected or directed by the influence of the magnetic field. Assuming the circular stream, the magnetic particles may be directed toward the inner edge of the stream thereby purging the outer edge of the stream of magnetic particles and leaving a high concentration of non-magnetic particles on the outer edge and creating a high density region of magnetic particles at the inner edge of the stream. Since the magnetic particles are immersed in a high density flux region along the width of the stream and since the flux density very considerably drops olf at the inside edge of the stream and finally drops to zero or elfectively zero, the non-magnetic particles are withdrawn through the preferably curved ports 76 and 78 or withdrawn in some other way, e.g. a suction tube, for quite easy recovery.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed. For example, in this type of separator the magnetic action may overlap the inner edge of pan 20 so that the magnetic particles are not only guided toward the inner parts 76 and 78 but also through these parts by the action of the magnetic field. This will happen when the inner parts 76, 78 and any others like them are in line with a pair of upper and lower ribs 69 and 70 (see Figure 3). A better efiiciency results from such an arrangement.

What is claimed as new is as follows:

1. In a device for magnetically separating magnetic and non-magnetic particles, the combination of an approximately flat circular pan having a bottom wall and side walls, means including an inlet port in the outer wall for introducing a heterogeneous stream of magnetic and non-magnetic particles tangentially into said pan and for propelling the stream in a circular path within the pan, means including a pair of flat circular pole pieces disposed above and below said pan for producing a magnetic field across said stream extending toward the inner edge of said path at an angle to the general direction of movement of said stream for magnetically deflecting the magnetic particles of said heterogeneous stream towards said inner edge, a portion of said pan at said inner edge 'having at least one outlet port through which the mag netic particles that are deflected by the magnetic field producing pole pieces are adapted to pass.

2. In a device for magnetically separating magnetic and non-magnetic particles, the combination of an approximately circular pan having a bottom wall and side Walls, means including an inlet port in the outer wall for introducing a heterogeneous stream of magnetic and nonmagnetic particles tangentially into said pan and for propelling the stream in a circular path within the pan, means including a pair of pole pieces on opposite sides of said stream for producing a magnetic field across said stream and at an angle to the general direction of movement of said stream for magnetically deflecting the magnetic particles of said heterogeneous stream while they continue to be propelled and toward one edge of said stream, a portion of said pan at the part of the stream having a higher concentration of magnetic particles having at least one outlet port through which the magnetic particles that are deflected by the magnetic field producing pole pieces are adapted to pass, said outer wall of said pan having at least one outlet port through which the non-magnetic particles of the stream are centrifugally propelled, said pole pieces each consisting essentially of a ring having a plurality of ribs which are spaced from each other and which have edges of small area, said ribs constituting a part of said means for producing a magnetic field, and said ribs formed in pairs with the two ribs of each pair spaced from each other across which a flux gap is produced, and portions of the'ribs of each pair having a greater spacing than the remaining portions of the same ribs of each pair so that the field strength at the wider gap between ribs of said pair is smaller than the field strength between the remaining portions of the ribs of each pair.

3. Apparatus for magnetically separating magnetic and non-magnetic particles comprising means for moving a heterogeneous stream of particles in a direction of flow with said stream defining in cross-section a height and width, means for producing a magnetic field of parallel flux lines across the height of said stream with said field at an acute angle to said direction of flow whereby said magnetic particles are diverted from said direction of flow at said acute angle with respect thereto, and means varying the intensity of said magnetic field along the width of the stream.

4. The combination of claim 3 wherein said stream is moved in an approximately circular path so that said parallel flux lines extend axially thereof.

5. The combination of claim 3 wherein said magnetic field has greater field intensity at a first edge of the stream and weaker field intensity at a second edge of the stream to thereby facilitate separation of the magnetic particles of the stream, a magnetic particle outlet formed adjacent said second edge.

6. The combination of claim 3 wherein additional spaced field producing means are provided, establishing identical strip magnetic fields of parallel flux lines across the height of said stream.

References Cited in the file of this patent UNITED STATES PATENTS 1,056,318 Bruck Mar. 18, 1913 

